InvertebrateIreland Online
InvertebrateIreland Online
A large (20-30mm.) beetle, distinctively light brown, heavy-looking and rather ponderous. It has black and white bands on the underside of the abdomen. The antennae are wonderful fan-like constructions (see photograph above). In flight, the Cockchafer makes a very distinctive humming sound. It is a powerful flier, though not an agile one. A second smaller species, the Northern Cockchafer Melontha hippocastani is also found in Ireland, but its status here is uncertain.
The adults appear in May, hence the alternative name Maybug. They feed mostly on the leaves, flowers and fruit of deciduous plants, mainly trees and especially oak. At dusk, in May and early June, huge swarms are sometimes seen around the tops of trees and shrubs. The larvae are chunky, white, curved, soil-dwelling grubs that feed on roots of both herbaceous and woody plants (see pest significance). The grub measures 10-20 mm in the autumn following its birth and 30-35 mm by autumn of the following year. Still as a grub it reaches its maximum size of 40-46 mm in the spring of its third year . Larvae pupate in the ground, usually in July. After five to six weeks the adults emerge only to hibernate in the soil until the following spring. The developmental cycle, then, lasts 36 months spread over 4 years (see example below). The "major flights" take place every 3 years -"cockchafer years " – but the year differs from one region to another.
| Year 1 | Year 2 | Year 3 | Year 4 |
| egg (May) first year larva | 2nd year larva | 3rd year larva; pupates July | hibernation until emergence as adult in May) |
Deciduous woodland and parkland and wooded urban areas.
A common European beetle found throughout Ireland (although not everywhere). It is especially common along the Lagan valley in Northern Ireland.
These days Cockchafers cause almost no damage at all. This is most probably due to the widespread use of mechanical cultivators that kill the very fragile larvae, and also due to the changes in production systems. A plague of Cockchafers was recorded in the west of Ireland during the summer of 1688, causing great damage "The whole country was left as bare and naked as it had been in the depth of winter, making a most unseemly and indeed frightful appearance". Such plagues occur occasionally in Scandinavia where they are responsible for reduced tree-rings (historic instances of which have sometimes been attributed to meteorite strike or volcanic eruptions).
These days Cockchafers cause almost no damage at all. This is most probably due to the widespread use of mechanical cultivators that kill the very fragile larvae, and also due to the changes in production systems. A plague of Cockchafers was recorded in the west of Ireland during the summer of 1688, causing great damage "The whole country was left as bare and naked as it had been in the depth of winter, making a most unseemly and indeed frightful appearance". Such plagues occur occasionally in Scandinavia where they are responsible for reduced tree-rings (historic instances of which have sometimes been attributed to meteorite strike or volcanic eruptions).
How did the Cockchafer beetle get its name?
The name "Cockchafer" is Old English for "big beetle" while "Kafer" is German for "beetle". The beetle belongs to the Scarab beetle family Scarabaeidae.
http://www.inra.fr/Internet/Produits/HYPPZ/RAVAGEUR/6melmel.html
The Burren, Co.Clare, 27 May 2004. © Brian Nelson
Copyright © National Museums of Northern Ireland, 2006.